Traditional high-intensity luminaries (also popularly termed “fixtures”) for installation in various indoor, outdoor and indoor/outdoor (e.g. parking areas) environments are weatherproof, having durable sealed lens covers that keep moisture, vapor and other contaminants away from their internal lamps, wiring and electrical components. Such luminaries are commonly termed “vapor-tight” fixtures/luminaries. These luminaries generally include a fluorescent lamp assembly within their housing. Currently available designs define a “clamshell” consisting of an elongated, opaque, upper box (typically of polymer material), having pendant mounting brackets, attached electronics (ballast, etc.), wiring, reflector assembly and a plurality of fluorescent lamps in a predetermined number and arrangement; a translucent lower lens having a top edge that mates with the bottom edge of the upper box; and a horizontally oriented and elongated sealing surface created by the upper housing and lower lens mating surfaces. This interface between the upper and lower portions of the luminaire incorporates an elastomeric-type gasket that creates a moisture and dust-resistant seal when a set of housing affixed sealing clamps are employed to compressibly join the housing and lens portions of the luminaire. However, the seal is subject to the effects of aging, and eventually fails over time. This is partially the result of the spacing between sealing clamps and the elongated nature of the horizontal sealing surface (which provides an uneven compression to the joint line) combined with aging of the materials, environmental changes and extremes in temperature. As the seal degrades it allows for the undesirable infiltration of moisture and contaminants. Because the seal is elongated and horizontal, it encourages the buildup and retention of moisture at the seal interface around the perimeter. The moisture seeks a lower level, which it achieves by migrating through any gaps in the seal around the relatively large and intermittently clamped perimeter. Once the moisture enters, it pools in the lens, causing fogging, staining of the lens and eventual failure of the wiring and electronics.
Shortened lamp and electronics (ballast, etc.) life due to moisture-based deterioration increases the costs of maintaining the luminaries, and shortened unit life leads to more frequent replacements and higher costs for the facility owner/operator.
A vapor-tight luminaire with an advanced and efficient reflector and lamp arrangement is provided in commonly assigned U.S. Pat. No. 7,588,347, entitled LIGHTING FIXTURE, by Richard D. Edwards, Jr., which is incorporated herein by reference as useful background information. This design provides superior optimetrics with two or three fluorescent lamps. However, it relies upon existing vapor-tight housing technology which has the disadvantages described generally above. Likewise, such “clamshell” housing designs are not adapted for upgrade to different lamp arrangements that may become available and/or desiravle over time—for example, upgrading to a different number/type of fluorescent bulbs.
It is, thus, highly desirable to provide a luminaire that uses fluorescent tubular lamps, or another type of elongated light source, which is vapor tight and reduces the deleterious effects on the housing and electronics brought upon by environmental conditions, among other factors. In particular, this luminaire should employ a housing arrangement that avoids the disadvantages of an elongated, horizontal intermittently clamped seal that is prone to accumulate moisture and allow it to migrate through a gap. This luminaire should be able to employ an advanced and efficient lamp arrangement and reflector design, and afford superior photometrics. This luminaire should be easily retrofit into existing structures in a variety of mounting arrangements, such as direct-to-ceiling, pendant, etc. Moreover, the underlying housing structure should allow for straightforward mounting and removal (i.e. upgrade) of a variety of lamp designs within a single housing enclosure.